Door opener



C. R. MOSS DOOR OPENER Dec. 2, 196 9 4 Sheets-Sheet 1 Filed Feb. 1, 1968ZN VENTOR. cmmas R. MOSQ AWTURNEYS c. R. MOSS DOOR OPENER Dec. 2, 1969 4Sheets-Sheet 2 Filed Feb. 1, 1968 INVENTOR. CA/ARL ES A. MOSS ,4TTOR/VEYS C. R. Moss DOOR OP ER Dec. 2 69 4 sheets heet 5 Filed Feb. 1,1968 Dec. 2, 1969 c, R. Moss 3,481,074

DOOR OPENER Filed Feb. 1, 1968 4 Sheets-Sheet 4 n FIGS 2 I v w INVENTOR.CHARLES R. M088 {M ATTUEMEKS' United States Patent 3,481,074 DOOR OPENERCharles R. Moss, Lyndhurst, Ohio, assignor to Eaton Yale & Towne Inc.,Cleveland, Ohio, a corporation of Ohio Filed Feb. 1, 1968, Ser. No.702,330 Int. Cl. E05d /38; E05f 15/16 U.S. Cl. 4928 16 Claims ABSTRACTOF THE DISCLOSURE Disclosed herein is a door operator assembly includinga drive mechanism for moving a door between a closed position and anOpen position and back to the closed position. The drive mechanismincludes a drive pulley rotatably mounted on a drive shaft and connectedby a cable to a carriage which is movable along a track to thereby pullthe door from the closed position to the open position. A torquetransmitting assembly drivingly connects the drive pulley to the driveshaft and enables the drive shaft to be rotated relative to the drivepulley when a load in excess of a predetermined magnitude is applied tothe drive pulley in either direction of pulley rotation. An actuatorassembly is mounted on the drive shaft and includes a threaded memberwhich is moved axially along the drive shaft to actuate a switch andthereby stop the operation of the door opener assembly.

This invention relates generally to a drive mechanism and moreparticularly to a drive mechanism for opening a door.

It is an object of this invention to provide a new and improved,relatively compact and inexpensive, drive mechanism for opening a door.

It is another object of this invention to provide a new and improveddrive mechanism mounted on a drive shaft and operatively connected to adoor for moving the door between a closed position and an pen positionand for actuating a switch to stop the operation of the drive mechanismwhen movement of the door is arrested.

It is another object of the inventi n to provide a drive mechanism foroperating a door between a closed position and an open position, saiddrive mechanism comprising a drive shaft adapted to be connected to asource of power, a drive pulley rotatably mounted on said drive shaftand drivingly connected to the door, torque transmitting means fortransmitting torque from the drive Y shaft to the drive pulley tothereby move the door from the closed position to the open position andfor enabling relative rotation to occur between the drive pulley and thedrive shaft in response to the door encountering an obstacle, switchmeans for controlling the operation of the drive mechanism, and anactuator assembly for operating the switch means upon the occurrence ofrelative rotation between the drive pulley and drive shaft.

It is another object of this invention to provide a new and improveddrive mechanism in accordance with the preceding paragraph and whereinthe actuator assembly includes an actuator means having a first set ofthreads formed thereon and a base having a sec nd set of threads formedthereon in meshing engagement with the first set of threads to therebyenable the actuator means to be moved in an axial direction relative tothe base upon the occurrence of relative rotation between the drivepulley and the drive shaft.

It is another object of this invention to provide a new and improveddrive mechanism for moving a door between a closed and an open position,said drive mechanism including a drive shaft adapted to be connected to"ice a source of power, a drive pulley mounted on the drive shaft anddrivingly connected to the door, torque transmitting means mounted onthe drive shaft and frictionally engaging one side of the drive pulleyfor drivingly connecting the drive pulley to the drive shaft to therebymove the door between the closed and open positions and for enabling thedrive shaft to rotate relative to the drive pulley, switch means forcontrolling the operation of the drive mechanism, and an actuatorassembly mounted on the drive shaft in frictional engagement withanother side of the drive pulley, the actuator assembly includingactuator means movable in an axial direction relative to the drivepulley to operate the switch means upon the occurrence of the rotationof the drive shaft relative to the drive pulley to thereby stopoperation of the drive mechanism.

It is another object of this invention to provide a new and improveddoor opener assembly for moving a door between closed and openpositions, the door opener assembly comprises a drive shaft adapted tobe connected to a source of power, a drive pulley mounted on the driveshaft, a carriage connected to the door and movable along a track tomove the door between the cl sed and open positions, cable means havingmore than one turn around the drive pulley for drivingly connecting thecarriage to the drive pulley, the drive pulley having a concave surfacefor lessening the cable scuffing effect of wrapping of the cable uponitself and for promoting engagement of the turns of the cable with thedrive pulley, drive means mounted on the drive shaft and engaging thedrive pulley for transmitting torque from the drive shaft to the drivepulley to thereby move the carriage to operate the door between a closedand open position and for enabling the drive shaft to rotate relative tothe drive pulley when a load applied to the drive pulley is equal to orgreater than a predetermined magnitude to thereby arrest movement of thecarriage along the track, switch means for controlling the operation fthe door opener assembly, and an actuator assembly for operating theswitch means, said actuator assembly including an actuator membermounted on the drive shaft in a coaxial relationship with the drivepulley for movement in an axial direction along the drive shaft tooperate the switch means when the load applied to the drive pulley is ofsufficient magnitude to result in rotation of the drive shaft relativeto the drive pulley.

These and other objects and features of the invention will become moreapparent upon a consideration of the following detailed descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is an elevational view of a door opener assembly for moving adoor from the closed position (shown) to an open position;

FIG. 2 is an elevational view, similar to FIG. 1, of a portion of thedoor assembly with the door in the open position;

FIG. 3 is an enlarged sectional view, taken along the line 33 of FIG. 2,illustrating the mounting of a carriage of the door opener assembly on aguide track;

FIG. 4 is an enlarged sectional view, taken along the line 4-4 of FIG.2, further illustrating the structure of the door opener assembly;

FIG. 5 is a sectional view, on an enlarged scale, of a drive mechanismfor operating the door opener assembly of FIG. 1, the drive mechanismbeing illustrated in a condition in which the door is closed;

FIG. 6 is a fragmentary elevational view, taken along the line 66 ofFIG. 5, further illustrating the structure of the drive mechanism;

FIG. 7 is an enlarged fragmentary elevational view, similar to FIG. 6,illustrating the drive mechanism when the door is in the open position;

FIG. 8 is a fragmentary sectional view, taken along the line 88 of FIG.7, further illustrating the drive mechanism; and

FIG. 9 is a schematic illustration of a control circuit for the dooropener assembly of FIG. 1.

This invention provides a reversible drive mechanism which isparticularly well adapted for use in opening and closing a door. Thedrive mechanism includes a drive pulley which is mounted on a driveshaft and drivingly engages a cable connected to the door. When a loadin excess of a predetermined amount is applied by the cable to the drivepulley, an actuator assembly is operated to actuate a switch to stop theoperation of the drive mechanism. A drive mechanism 10 constructed inaccordance with the present invention is illustrated in FIG. 1 in a dooroperating assembly 12 for operating a door 14 of a building 16 between aclosed position of FIG. 1 and an open position of FIG. 2.

In addition to the drive mechanism 10, the door operating assembly 12includes a carriage 20 which is mounted on a track 22 and is moved by acable 24 along the track to open and close the door 14. The carriage 20is mounted on the track 22 by a plurality of rollers 30 which engage thetubular track 22 in the manner shown in FIGS. 1 and 3. The tubular track22 is supported at one end by a support bracket 34 which is connected toa wall of the building 16. An opposite end of the track 22 is connectedby diverging mounting brackets 36 (FIG. 4) to a support member or strut40 which is connected to a ceiling of the building 16. The brackets 36engage opposite sides of a support bracket 44 upon which an idler pulley46 is rotatably mounted. The cable 24 extends between a drive pulley orcapstan 50 and the idler pulley 46.

The carriage 20 is connected to the door 14 to pull the door upwardlyfrom the closed position of FIG. 1 to the open position of FIG. 2 and toregulate downward movement when the door is moved from the open positionof FIG. 2 to the closed position of FIG. 1. Accordingly, a towbarassembly 54 is connected at an upper end 56 (see FIG. 3) to downwardlyextending mounting ears 58 formed on Side sections 60 and 62 of thecarriage 20. The towbar assembly 54 includes an upper portion 66 whichis connected to a lower portion 68. The lower portion 68 of the towbarassembly 54 is pivotally connected to a bracket 70 mounted on the door14. Suitable apertures 74 are provided in the upper towbar portion 66 toenable the length of the towbar assembly 54 to be adjusted. A support orguide track 78, of known construction, is provided for guiding themovement of the door between the closed and open positions.

Operation of the drive mechanism 10 results in the drive pulley 50 beingoperated in a counterclockwise direction (as viewed in FIG. 1) to movethe carriage 20 and door 14 from the closed position of FIG. 1 to theopen position of FIG. 2. When the carriage reaches a positioncorresponding to the open position for the door 14, the carriage engagesa stop member 82 which is fixedly connected to the guide track 22. Thecounterclockwise rotation of the drive pulley 50 is then stopped orhalted by frictional engagement or binding of the cable 24 on the drivepulley. A tensioning spring 84 is connected to the cable 24 by brackets86 and 88 to insure that the cable is held in a taut binding engagementwith the drive pulley 50.

The direction of rotation of the drive pulley 50 is reversed to enablethe door 14 to be moved gradually from the open position of FIG. 2 tothe closed position of FIG. 1 as the cable 24 is paid out by a run fromthe drive pulley 50. When the door reaches the closed position of FIG.1, the carriage 20 engages a shock absorb ing compression spring 83located in surrounding relationship to the tubular track 22 and a stopmember 85 as the door 14 engages a door sill to stop or arrest themovement of the carriage along the guide track 22.

The drive mechanism 10 (see FIG. 5) includes the drive pulley 50 whichis mounted on a drive shaft assembly 94 which is driven through a gearreduction assembly 96 by a motor 98 (FIG. 1). The drive shaft assembly94 includes a shaft 100 which is drivingly connected to the gearreduction assembly 96 and upon which a sleeve 102 is mounted. The shaft100 and sleeve 102 are fixedly interconnected by a pin 104. The sleeve102 is used in association with the shaft 100 since the sleeve can bereadily machined or worked to form recesses for engaging components ofthe drive mechanism 10.

A friction clutch or torque transmitting assembly 106 is mounted on thedrive shaft assembly 94 to transmit driving forces or torque from thedrive shaft assembly to the drive pulley 50 upon rotation of the driveshaft assembly. The torque transmitting assembly 106 also enables driveshaft assembly 94 to rotate relative to the drive pulley 50 when anamount of torque equal to the torque transmitting capacity of theassembly 106 is being transmitted to the drive pulley. The torquetransmitting assembly 106 includes a circular clutch or base plate 110mounted on the drive shaft assembly 94 in a coaxial relationship withthe drive pulley 50. The base plate 110 has a radially extending slot112 in which the pin 104 is received to retain the base plate 110against rotation relative to the drive shaft assembly 94 while enablingthe base plate 110 to be moved axially along the drive shaft. An annularfriction disk or ring 114 is secured to the base plate 110 and pressedinto frictional engagement with an annular side or friction surface 116of the drive pulley 50 by a spring assembly 120. The spring assembly 120is also mounted on the drive shaft assembly 94 and presses the baseplate 110 and friction ring 114 axially toward the drive pulley 50.Thus, the torque transmitting assembly 106 is mounted on the drive shaftassembly 94 in a coaxial relationship with the drive pulley 50 fordrivingly interconnecting the drive shaft 94 and drive pulley 50.

The torque or load which can be transmitted by the assembly 106 to thedrive pulley 50 is determined, in part, by the pressure which the springassembly 120 exerts on the base plate 110. Since the weight of the doorwith which the drive mechanism 10 is associated can vary in differentenvironments, an adjusting nut 124 is threaded onto the drive shaftassembly 94 for axial movement relative to the drive shaft to enable thepressure exerted by the spring assembly 120 against the base plate 110to be adjusted. In the present instance, the spring assembly 120includes a plurality of Belleville washers 126 which are relativelycompact and easily assembled on the drive shaft assembly 94. A springretaining washer 128 is provided between the nut 124 and the Bellevillewashers 126.

When a load in excess of the torque transmitting capability of theassembly 106 is applied to the drive pulley 50 by the cable 24, thedrive pulley 50 is held against rotation while the drive shaft assembly94 is rotated by the motor 98. Such a relatively large load is appliedto the drive pulley by engagement of the carriage 20 with one of thestops 82 or 85 when the door 14 is moved to open or close position orencounters an obstruction intermediate the stops. Sliding or slippingthen occurs between the drive pulley 50 and torque transmitting assembly106 and the drive shaft assembly 94 is rotated relative to the drivepulley. To facilitate this relative movement between the drive pulley 50and drive shaft assembly 94, a sleeve bearing 132 is mounted within thedrive pulley 50 for engagement with the drive shaft assembly 94. Athrust washer :of bearing 134 is engaged by a radially extending endsurface 136 of a drive pulley and is held by a keyed lock washer 140 andretainer ring 142 against axial movement relative to the drive shaftassembly 94 under the influence of the pressure exerted by the torquetransmitting assembly 106 against the opposite radially extending endsurface 116 of the drive pulley.

When a relatively large load is applied to the drive pulley 50 andrelative rotation occurs between the drive pulley and the drive shaftassembly 94, the drive pulley 50 is held by the cable 24 againstrotation under the influence of torque transmitted by the assembly 106.To insure that slipping or relative motion does not occur between thecable 24 and the drive pulley 50, the cable is wound for one and a halfturns around the drive p-ulley. In addition, the drive pulley 50includes inwardly sloping or concave surfaces 146 and 148 which tend tomake the turns of the cable center themselves against the drive pulleywithout crossing each other or moving laterally outwardly relative tothe drive pulley. The surfaces 146 and 148 promote this orientation ofthe cable by causing the turns of the cable to tend to move toward thecenter of the drive pulley where they engage the drive pulley and eachother without crossing to frictionally retard relative movement betweenthe drive pulley 50 and the cable. In one illustrative embodiment of theinvention, the surfaces 146 and 148 have an included angle ofapproximately one hundred and fifty degrees.

Of course, it is contemplated that the drive pulley 50 could be formedwith a shape other than the specific illustrated shape and that thecable 24 could be wound around the drive pulley for any desired numberof turns. The tapered surfaces 146 and 148 also lessen cable scuffingcaused by the natural tendency of the cable to overlap during winding onthe pulley 50 by reducing the work necessary to skid the underlying wrapof cable toward the center of the pulley 50.

An actuator assembly 150 is provided for operating a control switch 154to stop the motor 98 and, at the same time, provide for a reversal ofthe direction of operation of the motor on the next subsequent operationof the drive mechanism. The actuator assembly 150 is mounted on thedrive shaft assembly 94 in a coaxial relationship with the drive pulley50 and includes a generally circular base or body 158 which is rotatablerelative to the drive shaft assembly. The actuator base 158 has anannular end surface 160 which is pressed into frictional engagement withthe end surface 136 of the drive pulley 50 by a wave spring 164. Thesurface 160 of the actuator base 158 engages the end surface 136 of thedrive pulley 50 to transmit torque between the drive pulley 50 and theactuator assembly 150.

The switch 154 is operated by an actuator member 168 mounted on a base158 for movement in an axial direction relative to the drive shaftassembly 94 and the base 158. The actuator member 168 is movable betweena first position, shown in FIG 5, immediately adjacent to switch 154 anda second position (FIG. 8) in which the switch 154 is actuated oroperated by the member 168. Opening the door 14 results in the actuatormember being moved to the second position to actuate the switch 154.Closing the door 14 results in the actuator member 168 being moved tothe first position to release the switch 154.

This axial movement of the actuator member 168 is brought about by aninteraction between a first set of threads 172 extending in an axialdirection around an outer surface of the actuator base 158 and a secondset of threads 174 formed internally of an axial section 176 of theactuator member 168. The actuator member 168 is rotated relative to theactuator base 158 by a drive dog or member 180 when relative rotationoccurs between the drive pulley 50 and drive shaft assembly 94.Accordingly, the drive member 180 is retained against rotational andaxial movement relative to the drive shaft assembly 94 by a key section1 84 and a lock or snap ring 86. An axially projecting end portion 190of the drive member 180 extends through an opening 192 in a flangeportion 194 of the actuator member 168 (see FIG. 6) to interconnect thedrive member 180 and actuator member 168. Thus, when relative rotationoccurs between the drive shaft assembly 94 and the actuator body 158,the drive member 180 rotates the actuator member 168 relative to theactuator body 158 to move the actuator member 168 axially of theactuator body 158 under the influence of the threads 172 and 174 tothereby operate the switch 154.

A stop or pin 200 is fixedly mounted on the actuator body 158 forlimiting rotation and consequently axial movement, of the actuatormember 168 relative to the actuator body 158. The stop 200 is fixedlymounted in a hole or recess 202 in the actuator body 158 and extendsaxially outwardly into an arcuate recess 206 formed in the radiallyextending flange portion 194 of the actuator member 168 (see FIG. 6).When the actuator member 168 is rotated from the first position (FIGS. 5and 6) wherein the door 14 is open to the second position (FIGS. 7 and8) wherein the door 14 is closed, a radially extending end or stopsurface 210 of the arcuate opening 206 is moved into engagement with thestop member 200 to stop or arrest the rotation of the actuator member168 relative to the actuator body 158. Similarly, when the actuatormember 168 is rotated from the second position (FIGS. 7 and 8) to thefirst position (FIGS. 5 and 6), a second or opposite stop surface 212engages the stop member 200 to limit the rotation of the actuator member168.

When the drive mechanism 10 is operated to raise the door 14 from theclosed position to the open position, the drive pulley 50 rotates in acounterclockwise direction (as viewed in FIG. 1) to pull the carriage 20along the guide track 22 to the position shown in FIG. 2. When the door14 is opened, the carriage 20 engages the shock absorbing compressionspring 81 located in surrounding relationship to the tubular track 22and the stop member or collar 82 to halt or arrest the forward movementof the carriage. The rotation of the drive pulley 50' is then halted bya binding engagement between the cable 24 and the drive pulley. The loadwhich is applied to the drive pulley 50 by the cable 24 is then ofsuflicient magnitude to overcome the frictional torque transmitted bythe assembly 106 from the drive shaft assembly 94 to the drive pulley.Therefore, relative movement or slipping occurs between the drive pulley50 and the torque transmitting assembly 106. However, the actuatorassembly base 158 is held against rotation by the frictional engagementof the end surface 160 of the actautor base with the end surface 136 ofthe drive pulley 50.

The drive member 180 continues to rotate with the drive shaft assembly94 relative to the actuator base 158 and drive pulley 50. Therefore,when the door 14 reaches the open position, the actuator member 168 isrotated in a counterclockwise direction (as viewed in FIG. 6) relativeto the actuator body 158 by the drive member 180. As the actuator member168 is rotated relative to the actuator body 158, the meshing sets ofthreads 172 and 174 on the actuator member and body interact to move theactuator member 168 axially relative to the drive shaft assembly 94 fromthe position shown in FIG. 5 to the position shown in FIG. 8 to operatethe switch 154. Operation of the switch 154 deenergizes the motor 98 tohalt the rotation of the drive shaft assembly 94. It should be notedthat immediately after actuation of the switch 154, the stop surface 210engages the stop pin or member 200 (see FIG. 7). Therefore, the stopmember 200 will prevent further rotational and axial movement of theactuator member 168 relative to the actuator body 158 so that the forceapplied to the switch 154 does not become excessive. The actuatorassembly can then be rotated as a unit relative to the drive pulley 50by overcoming the frictional forces between the surface 136 of the drivepulley and the surface of the actuator body 158. This enables theactuator assembly 150 to oppose any coasting or inertial forcestransmitted from the motor 98 and reduction gear assembly 96.

Upon the next subsequent operation of the drive mechanism 10, thedirection of rotation of the motor 98 is reversed by the switch 154, ina manner to be explained in greater detail subsequently, to rotate thedrive pulley 50in a clockwise direction as viewed in FIG. 1. Theclockwise rotation of the pulley 50 pulls the carriage 20 toward thedrive mechanism 10 to close the door 14. When the door 14 is moved intothe closed position, the door engages an associated door sill and thecarriage 20 engages the stop member or collar 85 to thereby limit themovement of the carriage. Of course, the collar 85 could, if desired, bemoved to the left of the position shown in FIG. 1 to enable the movementof the carriage 20 to be arrested only by engagement of the door 14 withthe associated sill.

When the movement of the carriage 20 is stopped, the rotation of thedrive pulley 50 is also stopped by a binding action between the cable 24and the drive pulley 50 in a manner similar to that previouslyexplained. The rotation of the drive shaft assembly 94 will then becontinued to enable the drive member 180 to rotate the actuator member168 relative to the actuator body 156. As the actuator member 168 isrotated relative to the actuator body 158, the sets of threads 172 and174 cooperate to move the actuator member axially relative to the driveshaft 94 from the position shown in FIG. 8 to the position shown in FIG.to release the control switch 154.

If the door 14 should encounter an obstruction while moving from theopen position to the closed position, the downward movement of the doorwill be halted or arrested and the cable 24 will stop the rotation ofthe drive pulley 50. Rotation will then occur between the actuatormember 168 and the actuator body 158 to move the actuator memberinwardly to release the switch 154 in the manner previously explained.This operation of the switch 154 results in the motor being deenergized.Thus, the single control switch 154 is operative to stop the operationof the drive mechanism when the door is moved to either the open orclosed position and when the door engages the obstruction duringmovement from the open to the closed position. Of course, if the doorshould engage an obstruction while moving from the closed to the openposition, the drive mechanism would be operated in much the same manneras if the carriage had engaged the stop collar 82 to thereby stop theoperation of the drive mechanism.

A control circuit 230 for controlling the operation of the drivemechanism 10 is shown in FIG. 9. The control circuit 230 includes thereversing switch 154 which is operated by the actuator assembly 150 tostop the operation of the drive mechanism and to reverse the directionof rotation of the motor 98 on the next subsequent operation of thedrive mechanism. A start button or key 232 is provided in the controlcircuit for operating a stepper or control relay 234 to initiateoperation of the drive mechanism 10 to move the door 14 between theclosed and open positions. A receiver plug 236 is also provided forconnecting the control circuit 230 to an optional remote control device.In addition, the circuit 230 advantageously includes a light 238 forilluminating an area adjacent to the door 14 when the door is in theopen position.

The circuit 230 is shown in FIG. 9 with the door in the closed positionand the control switch 154 in the normal or released position of FIG. 5.Upon actuation of the push button 232, electrical energy is conductedfrom a transformer 242 to a coil 244 of the relay 234 to operate therelay from the position shown in solid lines in FIG. 9 to the positionshown in dashed lines in FIG. 9. Operation of the relay 234 completes acircuit for energizing the motor 98 from power lines 248 and 250. Thiscircuit includes a movable contact member 252 of the control switch 154which is in engagement with a fixed contact 256, a lead 258, a movablecontact 260 of the stepper relay 234, a field coil 262 of the motor 98,a second movable contact 264 of the stepper relay 234, and a lead 266which is connected to the armature coil 268 of the motor 98. Thearmature coil 268 is in turn connected by a lead 270 to the power line248. Thus, actuating the start switch or push button 232 operates therelay 234 to energize the field coil 262 of the motor 98 to rotate thedrive pulley 50in a counterclockwise direction, as viewed in FIG. 1, tothereby move the door 14 from the closed position to the open positionin the manner previously explained.

When the door 14 moves to the open position of FIG. 2, the controlswitch 154 is actuated, by the actuator member 168 in the mannerpreviously explained. Actuation of thecontrol switch 154 moves contact252 into engagement with the fixed contact 274, as shown in dashed linesin FIG. 9. This completes a circuit to energize the light 238 and opensthe previous circuit to deenergize the motor 98. The control switch 154remains in the operated position, indicated in dashed lines in FIG. 9until the door is closed.

When the start button 232 is again actuated to move the door 14 from theopen position to the closed position, the relay 234 is again stepped tomove the contacts 260 and 264 from the position shown in dashed lines tothe position shown in solid lines in FIG. 9. This operation of the relay234 energizes the motor for rotation in a direction opposite to itsprevious rotation so that the drive pulley 50 is rotated in a clockwisedirection as viewed in FIG. 1. Thus, the field coil 262 is energizedfrom the power line 250 through the movable contact 252 of the controlswitch 154 and the movable contact 264 of the relay 234 which is in aposition shown in solid lines in FIG. 9. The circuit is completed to thepower line 248 through the movable contact 260 of the relay 234, theline 266, the armature coil 268 and the line 270. When the door 14reaches the closed position, the rotation of the drive pulley is haltedor arrested and the actuator assembly operates the control switch 154 tothe position shown in solid lines in FIG. 9 to de-energize the motor 98and the light 238.

In view of the preceding description, it will be apparent that I haveprovided a drive mechanism 10 which is particularly well adapted for usein a door operator assembly. However, it is contemplated that theillustrated structure of the drive mechanism 10 will be varied somewhatwhen the drive mechanism is to be used in other environments. It is alsoanticipated that the structure of the door opener assembly 12 will bevaried in many different ways. For example, the particular structure ofthe guide track 22, carriage 20 and towbar assembly 54 could be variedwithout affecting the operation of the drive mechanism 10. It is furthercontemplated that the particular structure of the various components ofthe drive mechanism will be changed or modified by those skilled in theart. Therefore, it is intended to coverby the appended claims any suchmodifications or changes as fall within the true spirit and scope of theinvention.

What is claimed is:

1. A drive mechanism for operating a door between a closed position andan open position, said mechanism comprising a rotatable drive shaftadapted to be connected to a source of power, a drive pulley rotatablymounted on said drive shaft and operatively connected to said door,torque transmitting means for transmitting torque from said drive shaftto said drive pulley to thereby move said door between said positionsand for enabling relative rotation to occur between said drive pulleyand said drive shaft upon said drive pulley encountering a predeterminedresistance to rotation, switch means for controlling the operation ofsaid drive mechanism, and an actuator assembly for operating said switchmeans, said actuator assembly including a base mounted for rotation withsaid drive pulley, actuator means mounted on said base and rotatablerelative to said base in one direction to actuate said switch means uponsaid relative rotation between said drive pulley and said drive shaft,and stop means mounted on said base for retaining said actuator meansagainst continued rotation in said one direction relative to said baseafter operation of said switch means by said actuator means.

2. A drive mechanism as set forth in claim 1 wherein said actuatorassembly further includes a first set of threads formed on said actuatormeans and a second set of threads formed on said base in meshingengagement with said first set of threads to thereby enable saidactuator means to be moved in an axial direction relative to said driveshaft and said base upon said relative rotation between said drivepulley and said drive shaft.

3. A drive mechanism as set forth in claim 1 wherein said actuatorassembly further includes a drive member connected to said drive shaftfor rotating said actuator means relative to said base upon saidrelative rotation between said drive pulley and said drive shaft.

4. A drive mechanism as set forth in claim 1 wherein said basefrictional engages said drive pulley to retard relative rotation betweensaid base and drive pulley, said base being movable relative to saiddrive pulley against the influence of said frictional engagement byrotation of said drive shaft relative to said drive pulley afterengagement of said actuator means with said stop means.

5. A drive mechanism as set forth in claim 1 wherein said torquetransmitting means, said drive pulley and said actuator assembly aremounted in a coaxial relationship on said drive shaft for rotation withsaid drive shaft to move said door between said positions.

'6. A drive mechanism for operating a door between a closed position andan open position, said mechanism comprising a track, a carriage mountedfor movement along said track to move said door between said positions arotatable drive shaft adapted to be connected to a source of power, adrive pulley rotatably mounted on said drive shaft, cable means fordrivingly connecting said carriage to said rive pulley, spring means forresiliently urging said cable means into binding engagement with saiddrive pulley to thereby prevent slipping between said cable means andsaid drive pulley, torque transmitting means for transmitting torquefrom said drive shaft to said drive pulley to rotate said drive pulleyto move said cable means and carriage to operate said door between saidpositions and for enabling relative rotation to occur between said drivepulley and said drive shaft upon said drive pulley encountering apredetermined resistance to rotation, switch means for controlling theoperation of said drive mechanism, and an actuator assembly foroperating said switch means, said actuator assembly including a basemounted for rotation with said drive pulley and actuator means drivinglyconnected with said shaft and operatively connected to said base foraxial movement relative to said base and drive shaft to actuate saidswitch means upon said relative rotation between said drive pulley andsaid drive shaft.

7. A drive mechanism as set forth in claim 6 wherein said cable means iswrapped around said drive pulley for more than one turn and said drivepulley has a sloping surface for promoting centering of the cable onsaid drive pulley.

8. A drive mechanism for moving a door between a closed position and anopen position, said drive mechanism including a drive shaft adapted tobe connected to a source of power, a drive pulley rotatably mounted onsaid drive shaft and adapted to be drivingly connected to said door,torque transmitting means mounted on said drive shaft and frictionallyengaging one side of said drive pulley for drivingly connecting saiddrive pulley to said drive shaft to thereby move said door between saidpositions and for enabling said drive shaft to rotate relative to saiddrive pulley, switch means for controlling the operation of said drivemechanism, and an actuator assembly mounted on said drive shaft infrictional engagement with another side of said drive pulley, saidactuator assembly including actuator means drivingly connected to saidshaft and movable in an axial direction relative to said drive pulleyfor operating said switch means upon the occurrence of said rotation ofsaid drive shaft relative to said drive pulley to thereby stop operationof said drive mechanism.

9. A drive mechanism as set forth in claim 8 wherein said actuatorassembly includes a body means operably associated with said drivepulley and having threads for engaging corresponding threads on saidactuator means, said actuator means being moved in said axial directionrelative to said drive pulley by an interactionbetween the threads onsaid body means and the threads on said actuator means when said driveshaft is rotated relative to said drive pulley.

10. A drive mechanism as set forth in claim 9 wherein said body means isrotatable with said drive shaft relative to said drive pulley.

11. A drive mechanism as set forth in claim 9 wherein said actuatorassembly includes stop means mounted on said body means for arrestingmovement of said actuator means in said axial direction relative to saiddrive pulley with said threads on said body means in meshing engagementwith said threads on said actuator means after said actuator means hasmoved through a sufiicient distance to operate said switch means.

12. A drive mechanism as set forth in claim 8 wherein said torquetransmitting means includes a base means drivingly connected to saiddrive shaft and movable in an axial direction relative to said driveshaft, friction means mounted on said base means for engaging said drivepulley to drivingly interconnect said drive pulley and said drive shaftthrough said base means, and said spring means engaging said base meansfor resiliently pressing said friction means against said drive pulley.

13. A drive mechanism as set forth in claim 12 wherein said torquetransmitting means further includes means for adjusting the pressureapplied by said spring means in pressing said friction means againstsaid drive pulley.

14. A door opener assembly for moving a door between closed and openpositions, said assembly comprising a rotatable drive shaft adapted tobe connected to a source of power, a drive pulley rotatably mounted onsaid drive shaft, a track, a carriage operatively connected to said doorand movable along said track to move said door between said closed andopen positions cable means having more than one turn around said drivepulley for drivingly connecting said carriage to said drive pulley, saiddrive pulley having a generally concave surface for promoting winding ofsaid cable near the center of said drive pulley, drive means mounted onsaid drive shaft and engaging said drive pulley for transmitting torquefrom said drive shaft to said drive pulley to thereby move said carriageto operate said door between said closed and open positions and forenabling said drive shaft to rotate relative to said drive pulley when aload applied to said drive pulley by said cable means is equal to orgreater than a predetermined magnitude to thereby arrest movement ofsaid carriage in one direction along said track, switch means forcontrolling the operation of said door opener assembly, and an actuatorassembly for operating said switch means, said actuator assemblyincluding an actuator member mounted on said drive shaft for movement inan axial direction along said drive shaft to operate said switch meanswhen the load applied to said drive pulley by said cable means is ofsufficient magnitude to result in rotation of said drive shaft relativeto said drive pulley.

15. A drive assembly as set forth in claim 14 wherein said actuatorassembly further includes a body means mounted on said drive shaft inengagement with said drive pulley for transmitting up to a predeterminedamount of torque from said drive pulley to said actuator assembly andfor enabling relative rotation to occur between said drive pulley andactuator assembly after operation of said switch means by said actuatormember.

16. A drive assembly as set forth in claim 15 wherein said driveassembly further includes a first set of threads formed on said bodymeans and a second set of threads formed on said actuator member andengaging said first set of threads, said actuator member being movedaxially along said drive shaft by an interaction between said sets ofthreads when said drive shaft is rotated relative to said body means tothereby actuate said switch means.

References Cited UNITED STATES PATENTS 2,757,327 7/1956 Oliver 318-2652,922,638 1/1960 Smith 160-188 X I. KARL BELL, Primary Examiner US. Cl.X.R.

